1. Field of the Invention
The present invention relates to a semiconductor laser.
2. Description of the Related Art
U.S. Pat. No. 4,896,325 discloses a wavelength tunable semiconductor laser. In the wavelength tunable semiconductor laser, a gain region and a phase adjustment region are provided between two mirrors that are arranged at both ends. With the semiconductor laser described in U.S. Pat. No. 4,896,325, current is individually injected into the two mirrors at both ends, and reflection spectra of the two mirrors are adjusted, so that an emission wavelength is tuned.